Fluid gradient engine



Aug. 18, 1964 Filed July 13, 1961 E. G. PICKELS ETAL FLUID GRADIENT ENGINE 4 Sheets-Sheet 1 FIG.

EDWARD G. PICKELS JAMES H. BASSHAM INVENTORS waiv ATTORNEYS g- 1954 E. G. PICKELS ETAL 3,144,831

FLUID GRADIENT ENGINE Filed July 13} 1961 4 Sheets-Sheet 2 INVENTORS ATTORNEYS .0m 0w OwmOmm OOWONN Ovmofi O9 09 ON Om O On 0 EDWARD G. PICKELS JAMES H. BASSHAM 7 a m 0 h zOTZFOm 330 m0 wmmmomo ONN g- 18, 1964 E'. G. PICKELS ETAL 3,144,831

FLUID GRADIENT ENGINE Filed July 13, 196l 4 Sheets-Sheet 3 EDWARD G. PICKELS JAMES H. BASSHAM IN VENTORS ATTORNEYS Aug. 18, 1964 Filed July 13, 1961 4 Sheets-Sheet 4 207 209 209 209 9 Q V |99 |9| I93 203 201 20| 20| F |G 7 FIG. l2

EDWARD G PICKELS JAMES H. BASSHAM INVENTORS ATTORNEYS United States Patent 3,144,831 FLUID GRADIENT ENGINE Edward G. Pickels, Atherton, and James H. Bassham, San Jose, Calif., assignors to Beckman Instruments, Inc., a corporation of California Filed Juiy 13, 1961, Ser. No. 123,891 13 Claims. (Cl. 103-6) This invention relates to a fluid gradient engine and more particularly to a pump which operates to provide a continuous flow of a composite fluid comprising a variable proportion of individual fluids.

It is often necessary, particularly in centrifuging operations, to feed two fluids simultaneously at a constant overall flow rate. In addition it is often desirable to provide a variation in the concentration or proportion of the two liquids to be fed. For instance, in centrifuging a saturated sugar solution and water, it may be desirable to begin the operation with water alone and to progressively increase the proportion of saturated sugar solution. Throughout the entire centrifuging operation, however, the total flow rate of the water and the saturated sugar solution should be maintained constant.

In other applications it may be required to progressively vary density, pH, conductivity or some other property. The variation may be straight line exponential, or the like. However, the total flow rate of fluid outflow should be maintained independent of the ratio of the mixed fluids.

In the prior art at least two separate systems have been provided to perform this operation. In the first of these systems a group of containers is filled with different solutions. By shaping and properly interconnecting the containers a varying ratio of mixed fluids may be drawn off. This system, however, is limited to finite total volumes and may not be stopped during the course of the program to produce a constant ratio mixture. In addition, with this system of shaped containers, it is very ditficult to obtain abrupt changes in the proportions.

In another system of the prior art, fluids to be mixed have been placed in separate containers. Bodies having particular shapes are lowered into the containers at a predetermined rate thereby causing a displacement dependent upon the rate of lowering into the containers and the shape of the body. Here again it is realized that only finite total volumes may be employed and again the operation may not be stopped in mid-program to produce a constant ratio mixture.

Generally, this invention solves the problems of the prior art by providing a two stage pump. The first stage may pump afirst fluid. The intake stroke of the first stage may be interrupted by a cam in such a way as to limit the amount of fluid pumped to that amount required to produce the desired proportion of the first fluid in the final mixture. The first stage then pumps into the second, or final, stage during the latters intake cycle. A second fluid is also supplied to the second stage pump in an amount necessary to fill it during this intake stroke. In brief, the amount of the second fluid drawn in by the second stage is the difference in volume between the maximum capacity of the second stage and the volume of fluid received from the first stage. The mixture of the two fluids is then pumped out of the second stage to where it will be used or stored.

In order to provide an even final outflow, a plurality of second stage pumps may be employed which are phase timed such that at least one is always in its exhaust phase. By proper phasing the sum of the outputs of the various second stages may be made to produce a smooth and constant outflow rate.

While the action of drawing the two fluids into the second stage ordinarily allows suflicient mixing of the two 3,144,331 Patented Aug. 18, 1964 solutions, magnetic or other stirring means may be uti lized.

It is, therefore, a general object of this invention to provide a fluid gradient engine having a continuous flow.

It is a more particular object of this invention to pro= vide an engine for mixing two or more fluids in a controlled variable ratio, wherein the total output of the mixed fluids is independent of that ratio.

It is still another object of this invention to provide a fluid gradient engine having the above mentioned characteristics wherein the output has an even flow rate.

It is still another object of the invention to provide a fluid gradient engine having the above mentioned characterstics which is further characterized in that the variation of the controlled ratio may be stopped during the course of a pumping operation.

It is a further object of this invention to provide a fluid gradient engine having the above mentioned characteristics which is not limited to finite amount of total fluid to be pumped.

These and other objects and features of the invention will become more clearly apparent upon a review of the following description in conjunction with the accompanying drawing in which:

FIGURE 1 is a front elevational view, partly in section, of a fluid gradient engine in accordance with this invention;

FIGURE 2 is a sectional view along the line 22 of FIGURE 1;

FIGURES 3 to 6 are schematic views showing the operation of a fluid gradient engine in accordance with this invention;

FIGURE 7 is a schematic view of the embodiment shown in FIGURES 1 and 2;

FIGURE 8 is a curve showing the strokes of a plurality of second stage pumps for a machine as shown in FIGURE 1;

FIGURE 9 is a curve showing a composite total volume outflow produced by the several second stage pumps having strokes in accordance with FIGURE 8;

FIGURE 10 is a view along the line 10-10 of FIG- URE 1 showing a drive cam surface for a'second stage of the engine as shown in FIGURE 1;

FIGURE 11 is a schematic view of another embodiment of the invention wherein more than two fluids are combined to produce the composite fluid;

FIGURE 12 is an elevational view of a sheet metal program cam for use in another embodiment of the invention;

FIGURE 13 is a perspective view in its assembled condition of the program cam shown in FIGURE 12; and

FIGURE 14 is a view similar to FIGURE 10 but showing a drive cam for the first stage of the engine shown in FIGURE 1.

For a better understanding of the description of this invention, the definitions used for the several types of fluid flow considered herein is deemed appropriate. Thus, the term continuous, when related to fluid flow, connotes that the flow is not limited by finite volumes of fluid but that it may be continued for an indefinite period of time dependent only upon the need for the fluid and, possibly, the total time of a single rotation of the program cam, which will be explained more fully hereinafter. But even the total time of rotation for the program cam is not limited if the variation of the fluid ratio is repetitive one.

The term constant is used to define a flow which is constant over a period of time but not necessarily constant in the instantaneous sense. Thus, a constant flow may include a pulsating flow as well as a non-pulsating flow.

An even flow is one in which no pulsation occurs although the rate may be continuously varied.

While the preferred embodiment of the gradient engine in accordance with this invention is shown in FIG- URES l and 2, the principle of operation can be more clearly explained with respect to the simpler embodiment shown schematically in FIGURES 36. With respect to these figures only a single second stage pump is shown rather than three second, or final, stage pumps as in the preferred embodiment. However, the principles involved with only a single second stage pump are in general identical to those involved when a plurality of second stage pumps are used.

FIGURES 3 to 6 schematically show four separate phases of operation of fluid gradient engine in accordance with this invention. Referring particularly to FIGURE 3 the gradient engine includes a first stage and a second stage pump 151 and 153 respectively. The first stage pump 151 is selectively connected to a source 155 of a first fluid A through the valve 161, while the second stage of the pump 153 may be selectively coupled to a source 157 of a second fluid B through the line 159 and the valve 163. The first and second stage pumps 151 and 153 may be selectively interconnected through the valves 161 and 163 and the valve 163 selectively couples the second stage pump to the outflow line 164. As will be seen hereinafter, fluid flows into each stage from the left and is exhausted to the right as shown in FIGURES 3 to 6.

In each of FIGURES 3 to 6 it is noted that each of the pumps 151 and 153 include pistons 165 and 167 respectively, which are resiliently urged downwardly by the springs 169 and 171. A drive shaft 173 is utilized to rotate cams 175 and 177 which cooperate with cam followers 185 and 187 aflixed to the pistons 165 and 167 respectively. A second shaft 179 serves to rotate a cam 181 which cooperates with a cam follower 183 also affixed to the piston 165. The cams 175 and 177 serve to drive their respective pistons upwardly and to permit resiliently urged downward movement in accordance with the particular shape of the cam. As will be seen hereinafter the cam shapes are preferably such that the rate of filling the pump 153 is identical to the rate of discharging the pump 151. The cam 181 is employed to provide the desired variable proportion of the fluid A to be used in the total fluid outflow of the engine. This is accomplished, generally, by limiting the downward excursion of the piston 165 and thus limiting the amount of fluid taken into the pump 151.

In operation, then, during the first phase the valves 161' and 163 may be considered closed as seen in FIG- URE 3. The cams 175 and 177 are positioned and the shaft 1'73 is rotated such that the cam 175 permits the piston 165 to move downward while the cam 177 urges the piston 167 upward. Raising piston 167 causes the second stage 153 to be exhausted into the outflow line 164. The valve 163 being closed prevents fluid from the second stage 153 from flowing into the line 159 or into the first stage pump 151.

At the same time downward movement of the piston 165 causes flow into the first stage pump 151 from the source of fluid 155. The closed valve 161' prevents fluid from being drawn from the line 159. It is apparent that the amount of fluid drawn into the first stage 151 from the source of fluid 155 will be determined by the downward excursion of the piston 165. Thus when the downward movement of the piston 165 is interrupted by the position of the cam 181, the flow of fluid from the source 155 is stopped. Thus, the amount of fluid A drawn into the first stage 151 will be directly proportional to the radius of the cam 181 at that point of the cam which contacts the follower 183. It is apparent that, by proper cam shaping and rotation, the amount of fluid A drawn into the first stage may be varied in any manner during the operation of the engine. Moreover, by keeping the cam 181 stationary the amount of fluid A can be maintained constant throughout the entire operation of the engine or for any desired portion of the operation. In

addition, by proper cam cutting, the proportion can be made variable and constant throughout separate portions of the engine operation. Although the shaft 179 rotates with its associated cam 181 the rotation of this shaft is very much slower than that of the shaft 173 which actually drives the pistons. Thus, one or more upward and downward excursions of the piston 165 are caused by the cam 175 before the cam 181 can rotate an amount suflicient to drive the piston a measurable distance. The action of the cam 181, then, is not really that of a cam but rather of a variable or adjustable stop.

Referring to FIGURE 4, the second phase is shown wherein the motion of the piston 165 is stopped by the cam 181. Here, due to the shape of the cam and its rotation, the earn 175 has fallen away from the cam follower which is held in position by the cooperation of the cam 181 with its follower 183. The cam 177, however, continues to contact the follower 187 thereby causing continued exhaust from the stage 153 into the outflow line 164.

During the third phase, FIGURE 5, the valves 161' and 163 are open but the valves 161 and 163 are closed. Thus, the line 159, the first stage 151 and the second stage 153 are effectively joined together. It is noted at this point, that the piston 165 in the first stage remains motionless since the driving cam still does not meet the follower 185.

At this time, however, the plunger 167 is moving downwardly due to the operation of the cam 177 and fluid B is drawn from the source 157 through the line 159 into the second stage pump 153. Although there is clear communication between the first and second stage pumps no fluid will flow from the first to the second stage at this time since the piston 165 is motionless.

As seen in FIGURE 6, as the shaft 173 continues to rotate, the cam 175 finally contacts the follower and drives the plunger 165 upward. The cam surfaces 175 and 177 are such that the upward movement of the piston 165 is equal to the downward movement of the piston 167 at this time. In addition the cams are positioned such that the piston 165 reaches its apex at the same time as, or before, the piston 167 reaches its nadir. Thus, if the cylinders of both stages 151 and 153 are of the same diameter, the amount of fluid A forced out of the first stage 151 is equal to the amount of fluid drawn into the second stage 153. Consequently, the fluid from the first stage 151 will flow directly to the second stage 153 and no additional fluid B will be drawn through the line 159.

Since the second stage 153 is filled completely and emptied completely with each stroke, the total amount of fluid pumped out of the line 164 is constant, if the operating rate of the second stage 153 is constant, regardless of the respective amount of particular fluid from the first stage 151 or from the source 157. In addition it is noted that all of fluid A which is drawn into stage 151 is subsequently forced into stage 153. Thus, by varying the amount of fluid drawn into stage 151 the overall proportion of fluid A to fluid B through the outflow line 164 can be varied. The total amount of fluid pumped out of the line 164 may, if desired, be varied by varying the rotational rate of the shaft 173 which in effect, varies the rate of operation for the entire engine.

Although it is noted that the amount of fluid exhausted through the line 164 may be constant over a period of time regardless of the respective amounts of fluid A and fluid B, the actual flow through the line 164 is pulsating due to the reciprocating motion of the piston 167. As mentioned hereinabove this pulsating out flow is overcome by the use of a plurality of second stage pumps as shown in FIGURE 1. The principle of operation, however, is identical to that for the fluid gradient engine shown in FIGURES 3 to 6.

In FIGURE 7 a schematic view of the fluid gradient engine of FIGURES 1 and 2 is shown which depicts the interconnection of the various stages. It is seen that a first stage 189, which is similar to stage 151 in FIGURES 3 to 6, has its input connected to the source 191 of fluid A through a valve 193. Each of the second, or final, stage pumps X, Y and Z have their inputs connected to a source 199 of fluid B through their respective valves 201 and the line 202. In addition the inputs of each of the second stage pumps is connected to the output of the first stage pump 189 through valves 201, the line 202 and a valve 203. The output of each of the second stage pumps X, Y and Z is connected to a final outflow line 207 through their respective valves 209. By timing the operation of the valves 201 and 209 the combination of the three output stages operates as the engine of FIG- URES 3 to 6 except that an even flow is provided in the outflow line 207.

In using a plurality of second stages with only one first stage it must be realized that for effective mixing, the first stage should draw in its complement of fluid A and exhaust the same for each stroke of each of the second stages. Thus, if these second stages are used as shown in FIGURE 7, the cycle of the first stage pump must be three times as fast as the cycles of the three second stage pumps. With reference to FIGURES 3 to 6, then, it can be seen that for such a case this can be accomplished by rotating cam 175 three times faster than the cams 177 which are associated with each of the three second stages. Alternatively, this can be accomplished by shaping the cam 175 with three times as many rises as the cams 177 and rotating all of the cams at the same speed. Regardless of the means used to increase the speed of the first stage, it should be remembered that the rate of exhaust for the first stage should not be greater than the rate of intake of all of the second stages at a given time. With this precaution the exhaust of fluid A from the first stage will not flow into the line 202 toward the source of fluid B.

The actual operation of the engine as shown in FIG- URE 7 may be more clearly understood with respect to the curves shown in FIGURES 8 and 9. FIGURE 8 relates to the stroke of the pistons in the various second stages X, Y and Z. The position of the stroke is shown in relation to the degrees of rotation of the shaft upon which the drive cams for the second stage pumps are mounted. From 0 to approximately 150 it is noted that stage X is exhausting fluid while from 120 to 270 stage Y is exhausting. Similarly, from 240 through 360 to 30 stage Z is exhausting fluid.

Due to the action of the valves 101 and 209, the lines from the respective second stages X, Y and Z are placed in timed communication with the intake and the exhaust lines 202 and 207. It is seen from FIGURE 8 that during the first 30 of shaft rotation not only is stage X advancing in stroke but also stage Z is advancing. Thus, it is apparent that an overlap occurs when one stage takes over from another. This overlap provides smooth and even flow in the outflow line 207.

As seen from FIGURE 9 a single one of the stages X, Y or Z delivers the full outflow through a substantial portion of the cycle. During the transition period, when one stage takes over from another, the sum of the outputs of the two transition stages is equal to the full outflow rate. Thus, from 0 to 30 both the stages Z and X deliver fluid while between 120 and 150 both the stages X and Y deliver fluid. Between 30 and 120 the full delivery is accomplished by the stage X. Similar action occurs at the other transitions.

Referring now to FIGURES 1 and 2 a fluid gradient engine in accordance with the preferred embodiment of the invention is shown. FIGURES 1 and 2 are essentially detailed views of the engine shown in FIGURE 7. The engine includes a base member 11 and an upstanding wall 13 secured thereto. The first stage 14 and the Various second stages X, Y and Z are located along the wall 13. Mounting members 15, 16, 17 and 18, each associated with an individual stage, are secured at the upper end on one side of the vertical wall 13.

As can be seen more clearly in FIGURE 2 each of the mounting members 15, 16, 17 and 18 include upper and lower outwardly extending arms 21 and 23 respectively. A member 25 having a neck portion 27 and a shoulder 29 is rigidly secured in an opening 31 of each of the lower arms 23. The member 25 may be secured to the extension 23 by threaded connection, by force fit, or by any other suitable means.

The member 25 defines a through longitudinal port 33. The lower end of the member 25 includes a threaded portion 35 for engagement with the threaded opening of a sleeve 37.

Referring more particularly to FIGURE 1 it is noted that the sleeve 37 includes an inwardly extending annular flange 39 at its lower end. A spring barrel 43, having an outside diameter greater than the inside diameter of the flange 39, is retained tightly between the threadably joined flange 39 and the member 25 with the barrel opening in registry with the port 33. An annular resilient member 41 is interposed between the flange 39 and the barrel.

A syringe plunger 45 cooperates with the barrel 43 and is retained at the base of a cup 47 by means of a plate 49 and screws 51. The cup 47 serves to retain a solvent or lubricator such as water for the syringe. Thus, when solutions such as saturated sugar is pumped by the engine, the syringe plunger is continuously cleared of crystallized sugar.

The cup 47 is secured to, or forms a part of, the top of a shaft 53. A yoke 55 is affixed at the lower end of the shaft 53. Shafts 57 and 59 depend from the yoke 55 and through stationary guides 61 and 63. Collars 65 are secured on the shafts 57 and 59 and a compression spring 67 is fitted about the shafts between the guides 61 and collars 65. Thus, the shafts 57 and 59, the yoke 55, the cup 47 and the plunger 45 are resiliently urged in a downward direction.

Each of the yokes 55 also includes a cam follower 69 which cooperates with the cams 71 to 74 to urge the plungers 45 upward into the barrels 43 against the resilient action of the spring 67. Each of the cams 71 to 74 is secured about a common shaft 77 which is coupled by means of a gear train (not shown) to a motive means 79 which may be of the variable speed type, which speed variations may be adjusted by the handle 81. Thus, it is seen that by operation of the motive means 79 each of the plungers 45 are urged into the respective barrels 43 in accordance with the time sequence determined by the cam surfaces themselves. As mentioned hereinabove with respect to FIGURE 7, the cam 71 may be shaped difierently than cams 72-74 in order to activate the first stage three times faster than each of the three second stages. Alternatively, all the cams 72-74 may be of the same shape but the cam 71 being placed on a shaft three times faster than the other shaft 77.

Associated with the first stage pump 14 of the gradient engine a second cam follower 83 is affixed to the yoke 55. The cam follower 83 cooperates with the cam 85 to limit the downward stroke of the plunger 45 associated with that stage. To drive the cam 85 the shaft 77 extends through the gear box 87 and terminates in a worm gear (not shown). The worm gear drives a shaft 89 upon which a pinion 91 is releasably held by means of a knurled nut 93. The rotation of the pinion 91 activates another pinion 95 through an idler gear 97. The pinion 95 is secured to a shaft 99 by another knurled nut 100. The shaft 99 terminates with a worm gear (not shown), which is employed to drive a ring gear (not shown). The ring gear is concentric about the shaft 77 and is affixed to the cam 85 by means of a tube 101.

The pinion 97 is secured to a slidable member 103 having a slot therein. A thumb screw 105 serves to releasably retain the member 103 and consequently to selectively position the idler 97 into mating relationship with the pinions 91 and 95. In order to change the speed ratio between the shaft 77 (or the cams 71 to '74) and the cam 85 it is merely required that the pinions 91 and 95 be replaced with different size pinions and the idler 97 adjusted to take up the variation in pinion diameters.

Also coupled to the motive means 79 through a gear train (not shown) in the housing 107 is a first upper shaft 109 and a second upper shaft 111. The rotational velocity of the shaft 109 can be maintained the same as that of the shaft 77. Since the first stage 14 is to operate three times faster than the second stage, the rotational velocity of the shaft 111 may be maintained at three times the velocity of the shafts "i7 and 109.

Within the housing 107 the shaft 111 is coupled to the valve 113 by a Geneva movement (not shown). As seen in the drawing the valve 113 includes a housing 115 which communicates at its lower end through a line 117 to the upper mouth of the port 33 in the member 35. The upper portion of the housing includes openings to the lines 119 and 121 which communicate with the first fluid intake line 123 and the first fluid exhaust line 125 respectively.

The valve member 113 further includes a rotatable plug 127 which includes bores 129 and 131 which are crossed in at first common plane. It is noted from the drawing that with the body member 127 in the position shown, the bore 129 communicates between the lines 117 and 119. On the other hand, if the valve member 127 is rotated 180, the bore 131 will communicate between the lines 117 and 119.

In addition to the bores 129 and 131, bores 133 and 135 are crossed in a plane perpendicular to the plane defined by the bores 129 and 131. Thus, when the valve member 127 is rotated 90 from the position shown in FIGURE 1, the line 117 will be placed in communication with the line 121 through the bore 133. At a 180 rotation from this position the same line 117 will be in communication with the line 121 through the bore 135. Thus, it is seen that upon repeated rotations of the valve member 127 by 90 the line 117 is alternately placed in communication with the line 119 and the line 121.

The shaft 109 is coupled to each of the valves 137, 139 and 141 through additional Geneva movements (not shown). Each of the valves 137, 139 and 141 operate similar to the valve 113 but since the shaft 109 rotates at one-third of the speed of the shaft 111 each of these valves operates at one-third the speed of the valve 113. Moreover, each of the Geneva drives associated with the valves 137, 139 and 141 are positioned on the shaft 109 such that the valves operate 120 out of phase from each other. The Geneva drive for valve 137 is maintained in the housing 107 while the drives for the valves 139 and 141 are maintained in the housing 143. Each of the valves 137, 139 and 141 cooperates with its respective syringe acting as a second stage pump and provides communication from the line 145 alternately to the intake line 147 and the out flow line 149.

Thus, it is seen that the gradient engine shown in FIG- URES 1 and 2 generally comprises a two stage positive displacement pump with the second stage including multiple pumps. Valve means are associated with each stage for alternatively permitting inflow and out flow of fluid.

Referring more particularly to FIGURE 10, the shape of the identical earns 72, '73 and 74 is shown in detail and may be compared with the curves of FIGURE 8, particularly that for the stage X. The cam of FIGURE 10 is considered to rotate in the direction of the arrow. Thus, from to 30 the radius of the cam begins to increase and from 30 to 120 the increase in radius is proportional to the angle of rotation. From 120 to 150 the radius continues to increase but to a lesser degree providing the transitional overlap between two of the second stage pumps. Between 150 and 180 there is a dwell during which time the operation of the valves associated with the pump A may be rotated and positioned. From 180 to 210 the radius of the cam begins to decrease. From 210 to 270 the radius decreases in proportion to the angle of rotation.

It is noted that from 270 to 300 there is a slight detent in the surface of the cam shown in FIGURE 10. This detent is utilized in order to mix that portion of the fluid which may be retained by the valve itself. Thus, upon considering the fluid gradient engine as shown in FIGURE 1 when the pump is being filled through the line 147, the valve 137 and the line 145, a certain amount of fluid may be retained in the valve 137 itself. This fluid will be that last passed through the valve and in the operation as previously defined will be that as delivered from the first stage of the pump. Since the proportion of the first of the two fluids is dependent upon the exact measure of fluid delivered from the first stage pump it is desirable that this full amount of fluid be delivered through the second stage. Thus, while the valve still communicates between the lines 145 and 147 (270 to 285) a surplus amount of fluid is drawn into the second stage X, said surplus being the equivalent of such amount of fluid retained by the valve 137 itself. This surplus fluid is mixed in the second stage pump A and an equal portion of the mixed fluid is forced back through the valve toward the line 147 (285 to 300).

From 330 to 0 there is an additional dwell at which time the valve 137 may again be operated.

As can be seen from FIGURE 14, the cam 71 is similar to the cams 72-74 but that its surface is repeated three times. Thus each rise and fall of the cam surface shown in FIGURE 10 appears in the cam of FIGURE 14 between the angles of zero and 120. The variations are repeated from 120 to 240 and again from 240 to 360. With the cam 71 thus shaped the first stage is activated three times faster than each of the second stages. Referring to FIGURE 2, the cam 85, which rotates in the direction of the arrow, is considered. It is noted that the radius of the cam decreases in proportion to the angle of rotation. As the cam is slowly rotated it serves as a continually lowering stop for the first stage plunger. Consequently, as the pumping operation proceeds, greater amounts of fluid are permitted to be drawn in by the first stage and the concentration of this fluid in the final mixture is continually increased. It is obvious that other variations may be accomplished merely by changing the shape of the cam 85.

If the rotation of the cam is stopped, for instance by disengaging the idler 97 (FIGURE 1) the amount of fluid drawn in by the first stage will remain constant and the proportion of fluids in the final mixture will also remain constant. Additional fluids may be handled by merely utilizing an additional stage for each additional fluid. Referring to FIGURE 11, another embodiment of the invention is shown wherein more than two, in this instance three, fluids are employed to derive the composite final fluid. The layout of FIGURE 11 is similar to that of FIGURE 7' and like reference numerals are used for like elements. Thus, there are again three final stages X, Y and Z, each having an inlet valve 201 and an outlet valve 209 connected to the outflow line 207. In addition to the first stage 187, as in FIGURE 7, there is another stage 211 which may be called the second fluid stage. The first stage and the second fluid stage each include an inlet valve 193 and an outlet valve 203.

The inlet valve 193 of the stage 211 is connected to a source 191 of a first fluid A. The inlet of the stage 189, through its valve 193, is connected to a source 199 of a second fluid B and to the outlet of the stage 211 through its respective valve 203. The inlets of the various final stages X, Y and Z are connected through their respective valves 201 to a source 213 of a third fluid C and to the outlet of the stage 189 through its valve 203.

In the operation of the embodiment shown in FIGURE 11 the stage 211 draws a first fluid similarly to the stage 189 in the embodiment of FIGURE 7. Subsequently, the stage 211 exhausts its fluid into the inlet of stage 189. The program cam for the stage 189, in this case, will be cut so as to provide a fluid intake at the stage 189 which is the equivalent of the total of fluids A and B to be used in the desired proportion of the final composite fluid. Subsequently, the fluids A and B are discharged through the outlet valve 203 of the stage 18? to the inlet valves 201 to the second stages X, Y and Z. Thus, there is a series arrangement of stages wherein the fluids are accumulated in the early stages and subsequently transferred to the final stage.

It is apparent that rather than a series arrangement of a first stage and a second fluid stage (as shown in FIGURE 11) for more than two fluids, a parallel arrangement could be employed. Thus, the stages 189, and 211 could each have their inputs connected directly only to the respective fluids A and B and each have their outputs connected to the input valves 201 of the second stages. It will be remembered from above that it is desirable that the final stage draw in a volume of fluid at the same rate as the preceding stage exhausts it. When more than one preceding stage is exhausting fluid at the same time it is apparent that a diiferent flow rate is employed than when only one stage is exhausting. Thus, if the two fluids A and B are to be mixed in different proportions the exahust time of the two preceding stages then will of course, vary. Although the parallel arrangement will provide for more simple derivation of the cam used in the stage 189 it is apparent that the intake action of the various final stages X, Y and Z will be more problematic.

Referring particularly to FIGURES l2 and 13, a program cam in accordance with still another embodiment of the invention is shown. Although the cams shown in FIGURE 1 clearly provide an accurate action it is apparent that gradients in accordance with the various functions may be more easily constructed utilizing the program cam shown in FIGURES l2 and 13 as will become apparent hereinafter. In general, the cams shown in FIG- URES 12 and 13 employ a flat sheet of metal as shown in FIGURE 12 wherein the top edge 215 is cut in accordance with the desired function of the gradient. Subsequently, the sheet metal is wrapped in the form of a cylinder as shown in FIGURE 13 and inserted in a hub 217 having an axis 219. The axis 219 may be caused to rotate similarly to the tube 101 of FIGURE 1 but about a vertical axis rather than a horizontal axis. The edge 215 is rotated under the cam follower 83 of FIG- URE 1.

Thus, it is seen that a fluid gradient engine is provided wherein two or more fluids may be mixed in a controlled ratio which is independent of the total outflow rate.

We claim:

1. A fluid gradient engine comprising means for providing a continuous flow of a composite fluid from a plurality of sources, and control means connected to one of said sources for continually varying the output therefrom to said means for providing a continuous flow, and means connected to said control means for operating the control means in time synchronism with said means for providing a continuous flow.

2. A fluid gradient engine as defined in claim 1 wherein said means for providing a continuous flow further provides a constant flow.

3. A fluid gradient engine comprising a first stage and at least one second stage pump, a fluid flow line connected between said first and second stage pumps, said first and second stage pumps being of the piston type having. an intake and an exhaust stroke, means connected to said first stage pump for drawing a controlled amount of a first fluid into the first stage pump during the intake stroke thereof, means operable during the intake stroke of the second stage pump and connected to the first stage pump for emptying said first stage pump through said fluid flow line into said second stage pump, means connected to said second stage pump and also operable during the intake stroke thereof for filling said second stage pump with a second fluid, means connected to said second stage pump for emptying the same, and means connected to said means for drawing a controlled amount of the first fluid into the first stage pump and operable in time synchronism with said second stage pump for continuously varying the amount of fluid drawn into said first stage pump independently of the amount of fluid emptied from the second stage pump during a single exhaust stroke of the second stage pump.

4. A fluid gradient engine as defined in claim 3 wherein a plurality of second stage pumps are included.

5. A fluid gradient engine as defined in claim 3 wherein said means for drawing a controlled amount of fluid into said first stage pump comprises means for controlling the excursion of the first stage pump piston.

6. A fluid gradient engine as defined in claim 3 wherein said means for drawing a controlled amount of fluid into said first stage pump comprises means for controlling the intake excursion of the first stage pump piston.

7. A fluid gradient engine as defined in claim 6 wherein said means for controlling the intake excursion of said piston includes cam follower means aflixed to said pistons and continuously stop means juxtaposed said cam follower means for limiting the intake stroke of the piston in said positive displacement pump.

8. In a fluid gradient engine as defined in claim 7 wherein said adjustable stop means comprises a sheet of metal having one edge thereof cut in conformance with the curve of the desired function, said sheet of metal being formed in a cylinder.

9. A fluid gradient engine comprising a first stage pump and a plurality of second stage pumps, a fluid flow line connected between said first stage pump and each of said second stage pumps, means connected to all of said pumps for maintaining the operating cycle of said first stage faster than that of either of said second stage pumps by a multiple equal to the number of said second stage pumps, the cycles of the second stage pumps being out of phase with each other, means connected to said first stage pump for drawing a controlled amount of a first fluid into the same, means connected to said first stage pump for subsequently emptying the same into at least one of said second stage pumps during a single cycle of the first stage pump whereby during a complete cycle of either of the second stage pumps the first stage pump is emptied into each of the second stage pumps, means connected to said second stage pumps for filling the same with a second fluid and means connected to the second stage pumps for emptying the same.

10. A fluid gradient engine comprising a first stage pump and three second stage pumps, a fluid flow line connected between said first stage pump and each of said second stage pumps, means connected to all of said pumps for maintaining the cycle of the first stage pump three times faster than that of either of the second stage pumps, the cycle of each of said second stage pumps being out of phase of the cycle of either of the other of the second stage pumps, means connected to the first stage pump for drawing a controlled amount of fluid into the same during each cycle of its operation, means connected to the first stage pump for emptying the same during a cycle of its operation into at least one of said second stage pumps, means connected to the second stage pump for filling the same with a second fluid and means connected to the second stage pump for emptying the same.

11. A fluid gradient engine comprising a first stage pump and a plurality of second stage pumps, each of said second stage pumps being of the type having a finite discharge time, a fluid flow line connected between said first stage pump and each of said second stage pumps, means connected to each of said second stage pumps for maintaining the discharge time of each of said second stage pumps diflerent from the discharge time of any other, means connected to said first stage pump for drawing a controlled amount of fluid into the same, means connected to said first stage pump for subsequently emptying said first stage pump through said fluid flow line into said second stage pumps, means connected to said second stage pumps for filling the same with a second fluid, means connected to said second stage pumps for emptying the same, and means connected to the means for drawing a controlled amount of fluid into the first stage pump and operable in time synchronism with said second stage pumps for continuously varying the amount of fluid drawn into said first stage pump independently of the amount of fluid emptied from the second stage pumps during a single discharge time.

12. A fluid gradient engine comprising a first stage pump a second fluid pump and at least one cyclically operated final stage pump, a fluid flow line connected between all of said pumps, means connected to said first stage pump for drawing a controlled amount of a first fluid into the same, means connected to said first stage pump for subsequently emptying the same into said second fluid pump, means connected to said second fluid pump for filling the same with a second fluid, means connected to said second fluid pump for subsequently emptying the same into said final stage pump, means connected to the final stage pump for filling the same with an additional fluid, means connected to said final stage pump for emptying the same, and means connected to both said first stage pump and said second fluid pump and operable in time synchronism with said final stage pump for varying the amount of first and second fluid drawn into said first stage pump and said second fluid pump respectively, independent of the amount of fluid emptied from said final stage pump during a single cycle thereof.

13. A fluid gradient engine as defined in claim 12 wherein a plurality of final stage pumps are included.

References Cited in the file of this patent UNITED STATES PATENTS 532,637 Browne Jan. 15, 1895 595,942 Diehl Dec. 21, 1897 1,277,383 Cherry Sept. 3, 1918 1,375,200 Barnickel Apr. 19, 1921 1,428,204 Barnickel Sept. 5, 1922 1,483,143 Whitlock Feb. 12, 1924 1,907,486 Boileau May 9, 1933 2,013,017 Vogt Sept. 3, 1935 2,330,781 Langmyhr Sept. 28, 1943 2,612,839 Denny Oct. 7, 1952 2,796,240 Miller June 18, 1957 2,858,822 Staege Nov. 4, 1958 2,907,276 Mitchell Oct. 6, 1959 2,914,219 Chiantelassa Nov. 24, 1959 2,972,307 Wirsching Feb. 21, 1961 2,992,619 Nilges July 18, 1961 UNITED STATES PATENT OEFI-CE CERTIFICATE OF CORRECTION Patent No. 3 144,831 August 18 1964 Edward G9 Pickels et a1 Itis hereby certified that error appears in the above numbered pat-- ent requiring correction and that the said Letters Patent should read as corrected below.

Column 2 line 63, after "not" insert a column 2 line 64. after "repetitive" insert a column 5 line 418 for "101" read 201 column 6 line 17 for "spring read syringe column 10, line 26 after "continuously" insert adjustable Signed and sealed this 12th day of January 1965 (SEAL) Attest:

EDWARD J BRENNER Commissioner of Patents ERNEST vW. SWIDER At testing Officer 

1. A FLUID GRADIENT ENGINE COMPRISING MEANS FOR PROVIDING A CONTINUOUS FLOW OF A COMPOSITE FLUID FROM A PLURALITY OF SOURCES, AND CONTROL MEANS CONNECTED TO ONE OF SAID SOURCES FOR CONTINUALLY VARYING THE OUTPUT THEREFROM TO SAID MEANS FOR PROVIDING A CONTINUOUS FLOW, AND MEANS CONNECTED TO SAID CONTROL MEANS FOR OPERATING THE CONTROL MEANS IN TIME SYNCHRONISM WITH SAID MEANS FOR PROVIDING A CONTINUOUS FLOW. 